Field of the Invention
The present invention relates to an image processing method, and particularly relates to an image processing method in an information processing system such as a personal computer, a printing apparatus, etc.
Description of the Related Art
An outline (shape) of an object such as a character, a line, a graphic, etc. can be represented by a straight or curved line formed by sequentially connecting coordinates of a plurality of points. A connection path of such points is called a path. A drawing command to define an outline of an object using a point sequence with a determined connection order is called point sequence data. There are cases where a portion of an object defined by such point sequence data is lost as a result of rasterization processing. A portion of an object is likely to be lost especially when point sequence data undergoes N-up layout processing or resolution conversion processing for adjustment to the printing resolution of a print engine of a printing apparatus. In layout processing or resolution conversion processing on point sequence data, a host personal computer (host PC), a printing apparatus, or the like reduces the size of an object by converting the coordinates of each point included in the point sequence according to the reduction rate of the layout processing or the resolution ratio of the resolution conversion processing. When the size of the object is reduced, the width of a portion of the object becomes so narrow that depending on the resolution and fill rule in the rasterization, the portion may be lost. This problem is illustrated in FIG. 1. In FIG. 1, when the size of the character object “H” is reduced, the lateral line that is a part of the object is lost.
Japanese Patent Application Laid-Open No. 5-73026 discusses a method for avoiding loss of the width of an object represented by point sequence data as a result of rasterization processing. In this method, a lateral line portion of an object is identified based on a combination of the direction of a path connecting a first point, which is a previous point to a second point, to the second point in a point sequence, and the direction of a path connecting the second point to a third point, which is a subsequent point to the second point. Then, in the method, the coordinates of the points constituting the lateral line portion are shifted in a longitudinal direction to correct a path representing an outline (shape) of the lateral line portion.
In the method discussed in Japanese Patent Application Laid-Open No. 5-73026, a path representing an outline of any specific portion (lateral line portion) is corrected. In other words, even if the specific portion is wide enough not to be lost as a result of rasterization processing, the path representing the outline of the specific portion is corrected. Since the path of a portion that does not need to be corrected is also corrected, the shape of an object becomes different from the shape of the object represented by the original path.